Multi-speed planetary transmission

ABSTRACT

A multi-speed transmission including a plurality of planetary gearsets and a plurality of selective couplers to achieve at least nine forward speed ratios is disclosed. The plurality of planetary gearsets may include a first planetary gearset, a second planetary gearset, a third planetary gearset, and a fourth planetary gearset. The plurality of selective couplers may include a number of clutches and a number of brakes. The multi-speed transmission may have four planetary gearsets and six selective couplers. The six selective couplers may include three clutches and three brakes.

RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 15/278,586, filed Sep. 28, 2016, titled MULTI-SPEED PLANETARYTRANSMISSION, docket AT-P16015USU1, the entire disclosure of which isexpressly incorporated by reference herein.

FIELD OF THE DISCLOSURE

The present disclosure relates to a multi-speed transmission and inparticular to a multi-speed transmission including a plurality ofplanetary gearsets and a plurality of selective couplers to achieve atleast nine forward speed ratios and at least one reverse speed ratio.

BACKGROUND OF THE DISCLOSURE

Multi-speed transmissions use a plurality of planetary gearsets,selective couplers, interconnectors, and additional elements to achievea plurality of forward and reverse speed ratios. Exemplary multi-speedtransmissions are disclosed in US Published Patent Application No.2016/0047440, Ser. No. 14/457,592, titled MULTI-SPEED TRANSMISSION,filed Aug. 12, 2014, the entire disclosure of which is expresslyincorporated by reference herein.

SUMMARY

The present disclosure provides a multi-speed transmission including aplurality of planetary gearsets and a plurality of selective couplers toachieve at least nine forward speed ratios. The plurality of planetarygearsets may include a first planetary gearset, a second planetarygearset, a third planetary gearset, and a fourth planetary gearset. Theplurality of selective couplers may include a number of clutches and anumber of brakes. In one example, the present disclosure provides amulti-speed transmission having four planetary gearsets and sixselective couplers. The six selective couplers may include threeclutches and three brakes.

In some instances throughout this disclosure and in the claims, numericterminology, such as first, second, third, and fourth, is used inreference to various gearsets, gears, gearset components,interconnectors, selective couplers, and other components. Such use isnot intended to denote an ordering of the components. Rather, numericterminology is used to assist the reader in identifying the componentbeing referenced and should not be narrowly interpreted as providing aspecific order of components. For example, a first planetary gearsetidentified in the drawings may support any one of the plurality ofplanetary gearsets recited in the claims, including the first planetarygearset, the second planetary gearset, the third planetary gearset, andthe fourth planetary gearset, depending on the language of the claims.

According to an exemplary embodiment of the present disclosure, atransmission is provided. The transmission comprising at least onestationary member; an input member; a plurality of planetary gearsetsoperatively coupled to the input member; a plurality of selectivecouplers operatively coupled to the plurality of planetary gearsets; andan output member operatively coupled to the input member through theplurality of planetary gearsets. Each planetary gearset of the pluralityof planetary gearsets includes a sun gear, a plurality of planet gearsoperatively coupled to the sun gear, a planet carrier operativelycoupled to the plurality of planet gears, and a ring gear operativelycoupled to the plurality of planet gears. The plurality of planetarygearsets includes a first planetary gearset, a second planetary gearset,a third planetary gearset, and a fourth planetary gearset. Each of theplurality of selective couplers has an engaged configuration and adisengaged configuration. The plurality of selective couplers includes afirst number of clutches and a second number of brakes, the first numberbeing equal to the second number. The output member being fixedlycoupled to the ring gear of the third planetary gearset and the planetcarrier of the fourth planetary gearset. The input member is operativelycoupled to the plurality of planetary gearsets only through a subset ofthe first number of clutches. The first number of clutches including afirst clutch, a second clutch, and a third clutch. The subset includesthe first clutch and the second clutch. The first clutch, when engaged,fixedly couples the input member to a first group of the plurality ofplanetary gearsets. The second clutch, when engaged, fixedly couples theinput member to a second group of the plurality of planetary gearsets.

According to another exemplary embodiment of the present disclosure, atransmission is provided. The transmission comprising at least onestationary member; an input member rotatable relative to the at leastone stationary member; a plurality of planetary gearsets operativelycoupled to the input member; and an output member operatively coupled tothe input member through the plurality of planetary gearsets androtatable relative to the at least one stationary member. Each of theplurality of planetary gearsets includes a first gearset component, asecond gearset component, and a third gearset component. The pluralityof planetary gearsets includes a first planetary gearset, a secondplanetary gearset, a third planetary gearset, and a fourth planetarygearset. The output member is fixedly coupled to the second gearsetcomponent of the fourth planetary gearset and to the third gearsetcomponent of the third planetary gearset. The transmission furthercomprising a first interconnector which fixedly couples the thirdgearset component of the first planetary gearset, the second gearsetcomponent of the third planetary gearset, and the third gearsetcomponent of the fourth planetary gearset together; a secondinterconnector which fixedly couples the third gearset component of thesecond planetary gearset to the first gearset component of the thirdplanetary gearset; a third interconnector which fixedly couples thesecond gearset component of the first planetary gearset to the firstgearset component of the second planetary gearset; and a plurality ofselective couplers. The plurality of selective couplers includes a firstselective coupler which, when engaged, fixedly couples the third gearsetcomponent of the first planetary gearset, the second gearset componentof the third planetary gearset, and the third gearset component of thefourth planetary gearset to the at least one stationary member; a secondselective coupler which, when engaged, fixedly couples the first gearsetcomponent of the first planetary gearset to the at least one stationarymember; a third selective coupler which, when engaged, fixedly couplesthe second gearset component of the second planetary gearset to the atleast one stationary member; a fourth selective coupler which, whenengaged, fixedly couples the input member to the second gearsetcomponent of the first planetary gearset and to the first gearsetcomponent of the second planetary gearset; a fifth selective couplerwhich, when engaged, fixedly couples the input member to the firstgearset component of the fourth planetary gearset; and a sixth selectivecoupler which, when engaged, fixedly couples the first gearset componentof the third planetary gearset and a first one of the first gearsetcomponent of the second planetary gearset, the second gearset componentof the second planetary gearset, and the third gearset component of thesecond planetary gearset to the second gearset component of the firstplanetary gearset and a second one of the first gearset component of thesecond planetary gearset, the second gearset component of the secondplanetary gearset, and the third gearset component of the secondplanetary gearset.

According to yet another exemplary embodiment of the present disclosure,a transmission is provided. The transmission comprising at least onestationary member; an input member rotatable relative to the at leastone stationary member; a plurality of planetary gearsets operativelycoupled to the input member; and an output member operatively coupled tothe input member through the plurality of planetary gearsets androtatable relative to the at least one stationary member. Each of theplurality of planetary gearsets includes a first gearset component, asecond gearset component, and a third gearset component. The pluralityof planetary gearsets includes a first planetary gearset, a secondplanetary gearset, a third planetary gearset, and a fourth planetarygearset. The output member is fixedly coupled to the second gearsetcomponent of the fourth planetary gearset and to the third gearsetcomponent of the third planetary gearset. The transmission furthercomprising a first interconnector which fixedly couples the thirdgearset component of the fourth planetary gearset to the second gearsetcomponent of the third planetary gearset; a second interconnector whichfixedly couples the first gearset component of the third planetarygearset to the third gearset component of the second planetary gearset;a third interconnector which fixedly couples the third gearset componentof the first planetary gearset to the first gearset component of thesecond planetary gearset; a fourth interconnector which fixedly couplesthe second gearset component of the first planetary gearset to thesecond gearset component of the second planetary gearset; and aplurality of selective couplers. The plurality of selective couplersincludes a first selective coupler which, when engaged, fixedly couplesthe third gearset component of the fourth planetary gearset and thesecond gearset component of the third planetary gearset to the at leastone stationary member; a second selective coupler which, when engaged,fixedly couples the second gearset component of the first planetarygearset and the second gearset component of the second planetary gearsetto the at least one stationary member; a third selective coupler which,when engaged, fixedly couples the first gearset component of the firstplanetary gearset to the at least one stationary member; a fourthselective coupler which, when engaged, fixedly couples the input memberto the third gearset component of the first planetary gearset and to thefirst gearset component of the second planetary gearset; a fifthselective coupler which, when engaged, fixedly couples the input memberto the first gearset component of the fourth planetary gearset; and asixth selective coupler which, when engaged, fixedly couples the thirdgearset component of the first planetary gearset and the first gearsetcomponent of the second planetary gearset to the second gearsetcomponent of the third planetary gearset and the third gearset componentof the fourth planetary gearset.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of thisdisclosure, and the manner of attaining them, will become more apparentand will be better understood by reference to the following descriptionof exemplary embodiments taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a diagrammatic view of an exemplary multi-speed transmissionincluding four planetary gearsets and six selective couplers;

FIG. 2 is a truth table illustrating the selective engagement of the sixselective couplers of FIG. 1 to provide ten forward gear or speed ratiosand a reverse gear or speed ratio of the multi-speed transmission ofFIG. 1;

FIG. 3 is a diagrammatic view of another exemplary multi-speedtransmission including four planetary gearsets and six selectivecouplers; and

FIG. 4 is a truth table illustrating the selective engagement of the sixselective couplers of FIG. 3 to provide ten forward gear or speed ratiosand a reverse gear or speed ratio of the multi-speed transmission ofFIG. 3.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate exemplary embodiments of the invention and suchexemplifications are not to be construed as limiting the scope of theinvention in any manner.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference is now made to the embodiments illustratedin the drawings, which are described below. The embodiments disclosedbelow are not intended to be exhaustive or limit the present disclosureto the precise form disclosed in the following detailed description.Rather, the embodiments are chosen and described so that others skilledin the art may utilize their teachings. Therefore, no limitation of thescope of the present disclosure is thereby intended. Correspondingreference characters indicate corresponding parts throughout the severalviews.

In the disclosed transmission embodiments, selective couplers aredisclosed. A selective coupler is a device which may be actuated tofixedly couple two or more components together. A selective couplerfixedly couples two or more components to rotate together as a unit whenthe selective coupler is in an engaged configuration. Further, the twoor more components may be rotatable relative to each other when theselective coupler is in a disengaged configuration. The terms “couples”,“coupled”, “coupler” and variations thereof are used to include botharrangements wherein the two or more components are in direct physicalcontact and arrangements wherein the two or more components are not indirect contact with each other (e.g., the components are “coupled” viaat least a third component), but yet still cooperate or interact witheach other.

A first exemplary selective coupler is a clutch. A clutch couples two ormore rotating components to one another so that the two or more rotatingcomponents rotate together as a unit in an engaged configuration andpermits relative rotation between the two or more rotating components inthe disengaged position. Exemplary clutches may be shiftablefriction-locked multi-disk clutches, shiftable form-locking claw orconical clutches, wet clutches, or any other known form of a clutch.

A second exemplary selective coupler is a brake. A brake couples one ormore rotatable components to a stationary component to hold the one ormore rotatable components stationary relative to the stationarycomponent in the engaged configuration and permits rotation of the oneor more components relative to the stationary component in thedisengaged configuration. Exemplary brakes may be configured asshiftable-friction-locked disk brakes, shiftable friction-locked bandbrakes, shiftable form-locking claw or conical brakes, or any otherknown form of a brake.

Selective couplers may be actively controlled devices or passivedevices. Exemplary actively controlled devices include hydraulicallyactuated clutch or brake elements and electrically actuated clutch orbrake elements. Additional details regarding systems and methods forcontrolling selective couplers are disclosed in the above-incorporatedUS Published Patent Application No. 2016/0047440.

In addition to coupling through selective couplers, various componentsof the disclosed transmission embodiments may be fixedly coupledtogether continuously throughout the operation of the disclosedtransmissions. Components may be fixedly coupled together eitherpermanently or removably. Components may be fixedly coupled togetherthrough spline connections, press fitting, fasteners, welding, machinedor formed functional portions of a unitary piece, or other suitablemethods of connecting components.

The disclosed transmission embodiments include a plurality of planetarygearsets. Each planetary gearset includes at least four components: asun gear; a ring gear; a plurality of planet gears; and a carrier thatis rotatably coupled to and carries the planet gears. In the case of asimple planetary gearset, the teeth of the sun gear are intermeshed withthe teeth of the planet gears which are in turn intermeshed with theteeth of the ring gear. Each of these components may also be referred toas a gearset component. It will be apparent to one of skill in the artthat some planetary gearsets may include further components than thoseexplicitly identified. For example, one or more of the planetarygearsets may include two sets of planet gears. A first set of planetgears may intermesh with the sun gear while the second set of planetgears intermesh with the first set of planet gears and the ring gear.Both sets of planet gears are carried by the planet carrier.

One or more rotating components, such as shafts, drums, and othercomponents, may be collectively referred to as an interconnector whenthe one or more components are fixedly coupled together. Interconnectorsmay further be fixedly coupled to one or more gearset components and/orone or more selective couplers.

An input member of the disclosed transmission embodiments is rotated bya prime mover. Exemplary prime movers include internal combustionengines, electric motors, hybrid power systems, and other suitable powersystems. In one embodiment, the prime mover indirectly rotates the inputmember through a clutch and/or a torque converter. An output member ofthe disclosed transmission embodiments provides rotational power to oneor more working components. Exemplary working components include one ormore drive wheels of a motor vehicle, a power take-off shaft, and othersuitable devices. The output member is rotated based on theinterconnections of the gearset components and the selective couplers ofthe transmission. By changing the interconnections of the gearsetcomponents and the selective couplers, a rotation speed of the outputmember may be varied from a rotation speed of the input member.

The disclosed transmission embodiments are capable of transferringtorque from the input member to the output member and rotating theoutput member in at least nine forward gear or speed ratios relative tothe input member, illustratively ten forward gear or speed ratios, andone reverse gear or speed ratio wherein the rotation direction of theoutput member is reversed relative to its rotation direction for the atleast nine forward ratios. Exemplary gear ratios that may be obtainedusing the embodiments of the present disclosure are disclosed herein. Ofcourse, other gear ratios are achievable depending on thecharacteristics of the gearsets utilized. Exemplary characteristicsinclude respective gear diameters, the number of gear teeth, and theconfigurations of the various gears.

FIG. 1 is a diagrammatic representation of a multi-speed transmission100. Multi-speed transmission 100 includes an input member 102 and anoutput member 104. Each of input member 102 and output member 104 isrotatable relative to at least one stationary member 106. An exemplaryinput member 102 is an input shaft or other suitable rotatablecomponent. An exemplary output member 104 is an output shaft or othersuitable rotatable component. An exemplary stationary member 106 is ahousing of multi-speed transmission 100. The housing may include severalcomponents coupled together.

Multi-speed transmission 100 includes a plurality of planetary gearsets,illustratively a first planetary gearset 108, a second planetary gearset110, a third planetary gearset 112, and a fourth planetary gearset 114.In one embodiment, additional planetary gearsets may be included.Further, although first planetary gearset 108, second planetary gearset110, third planetary gearset 112, and fourth planetary gearset 114 areillustrated as simple planetary gearsets, it is contemplated thatcompound planetary gearsets may be included in some embodiments.

In one embodiment, multi-speed transmission 100 is arranged asillustrated in FIG. 1, with first planetary gearset 108 positionedbetween a first location or end 116 at which input member 102 entersstationary member 106 and second planetary gearset 110, second planetarygearset 110 is positioned between first planetary gearset 108 and thirdplanetary gearset 112, third planetary gearset 112 is positioned betweensecond planetary gearset 110 and fourth planetary gearset 114, andfourth planetary gearset 114 is positioned between third planetarygearset 112 and a second location or end 118 at which output member 104exits stationary member 106. In alternative embodiments, first planetarygearset 108, second planetary gearset 110, third planetary gearset 112,and fourth planetary gearset 114 are arranged in any order relative tolocation 116 and location 118. In the illustrated embodiment of FIG. 1,each of first planetary gearset 108, second planetary gearset 110, thirdplanetary gearset 112, and fourth planetary gearset 114 are axiallyaligned. In one example, input member 102 and output member 104 are alsoaxially aligned with first planetary gearset 108, second planetarygearset 110, third planetary gearset 112, and fourth planetary gearset114. In alternative embodiments, one or more of input member 102, outputmember 104, first planetary gearset 108, second planetary gearset 110,third planetary gearset 112, and fourth planetary gearset 114 are offsetand not axially aligned with the remainder.

First planetary gearset 108 includes a sun gear 120, a planet carrier122 supporting a plurality of planet gears 124, and a ring gear 126.Second planetary gearset 110 includes a sun gear 130, a planet carrier132 supporting a plurality of planet gears 134, and a ring gear 136.Third planetary gearset 112 includes a sun gear 140, a planet carrier142 supporting a plurality of planet gears 144, and a ring gear 146.Fourth planetary gearset 114 includes a sun gear 150, a planet carrier152 supporting a plurality of planet gears 154, and a ring gear 156.

Multi-speed transmission 100 further includes a plurality of selectivecouplers, illustratively a first selective coupler 162, a secondselective coupler 164, a third selective coupler 166, a fourth selectivecoupler 168, a fifth selective coupler 170, and a sixth selectivecoupler 172. In the illustrated embodiment, first selective coupler 162,second selective coupler 164, and third selective coupler 166 are brakesand fourth selective coupler 168, fifth selective coupler 170, and sixthselective coupler 172 are clutches. The axial locations of the clutchesand brakes relative to the plurality of planetary gearsets may bealtered from the illustrated axial locations.

Multi-speed transmission 100 includes several components that areillustratively shown as being fixedly coupled together. Input member 102is fixedly coupled to fourth selective coupler 168 and fifth selectivecoupler 170. Output member 104 is fixedly coupled to planet carrier 152of fourth planetary gearset 114 and ring gear 146 of third planetarygearset 112. Ring gear 126 of first planetary gearset 108, planetcarrier 142 of third planetary gearset 112, ring gear 156 of fourthplanetary gearset 114, and first selective coupler 162 are fixedlycoupled together. Ring gear 136 of second planetary gearset 110, sungear 140 of third planetary gearset 112, and sixth selective coupler 172are fixedly coupled together. Planet carrier 122 of first planetarygearset 108, fourth selective coupler 168, sun gear 130 of secondplanetary gearset 110, and sixth selective coupler 172 are fixedlycoupled together. Sun gear 150 of fourth planetary gearset 114 isfixedly coupled to fifth selective coupler 170. Sun gear 120 of firstplanetary gearset 108 is fixedly coupled to second selective coupler164. Planet carrier 132 of second planetary gearset 110 is fixedlycoupled to third selective coupler 166.

Multi-speed transmission 100 may be described as having eightinterconnectors. Input member 102 is a first interconnector that bothprovides input torque to multi-speed transmission 100 and fixedlycouples fourth selective coupler 168 to fifth selective coupler 170.Output member 104 is a second interconnector that both provides outputtorque from multi-speed transmission 100 and fixedly couples planetcarrier 152 of fourth planetary gearset 114 to ring gear 146 of thirdplanetary gearset 112. A third interconnector 180 fixedly couples ringgear 126 of first planetary gearset 108, planet carrier 142 of thirdplanetary gearset 112, ring gear 156 of fourth planetary gearset 114,and first selective coupler 162 together. A fourth interconnector 182fixedly couples ring gear 136 of second planetary gearset 110, sun gear140 of third planetary gearset 112, and sixth selective coupler 172together. A fifth interconnector 184 fixedly couples planet carrier 122of first planetary gearset 108, sun gear 130 of second planetary gearset110, fourth selective coupler 168, and sixth selective coupler 172together. A sixth interconnector 186 fixedly couples sun gear 150 offourth planetary gearset 114 to fifth selective coupler 170. A seventhinterconnector 188 fixedly couples sun gear 120 of first planetarygearset 108 to second selective coupler 164. An eighth interconnector190 fixedly couples planet carrier 132 of second planetary gearset 110to third selective coupler 166.

Multi-speed transmission 100 further includes several components thatare illustratively shown as being selectively coupled together throughselective couplers. First selective coupler 162, when engaged, fixedlycouples ring gear 156 of fourth planetary gearset 114, planet carrier142 of third planetary gearset 112, and ring gear 126 of first planetarygearset 108 to stationary member 106. When first selective coupler 162is disengaged, ring gear 156 of fourth planetary gearset 114, planetcarrier 142 of third planetary gearset 112, and ring gear 126 of firstplanetary gearset 108 may rotate relative to stationary member 106.

Second selective coupler 164, when engaged, fixedly couples sun gear 120of first planetary gearset 108 to stationary member 106. When secondselective coupler 164 is disengaged, sun gear 120 of first planetarygearset 108 may rotate relative to stationary member 106.

Third selective coupler 166, when engaged, fixedly couples planetcarrier 132 of second planetary gearset 110 to stationary member 106.When third selective coupler 166 is disengaged, planet carrier 132 ofsecond planetary gearset 110 may rotate relative to stationary member106.

Fourth selective coupler 168, when engaged, fixedly couples input member102 to planet carrier 122 of first planetary gearset 108 and sun gear130 of second planetary gearset 110. When fourth selective coupler 168is disengaged, planet carrier 122 of first planetary gearset 108 and sungear 130 of second planetary gearset 110 may rotate relative to inputmember 102.

Fifth selective coupler 170, when engaged, fixedly couples input member102 to sun gear 150 of fourth planetary gearset 114. When fifthselective coupler 170 is disengaged, sun gear 150 of fourth planetarygearset 114 may rotate relative to input member 102.

Sixth selective coupler 172, when engaged, fixedly couples planetcarrier 122 of first planetary gearset 108 and sun gear 130 of secondplanetary gearset 110 to ring gear 136 of second planetary gearset 110and sun gear 140 of third planetary gearset 112. When sixth selectivecoupler 172 is disengaged, planet carrier 122 of first planetary gearset108 and sun gear 130 of second planetary gearset 110 may rotate relativeto ring gear 136 of second planetary gearset 110 and sun gear 140 ofthird planetary gearset 112.

As mentioned, when sixth selective coupler 172 is engaged, sun gear 130of second planetary gearset 110 and ring gear 136 of second planetarygearset 110 are locked together. Hence, sun gear 130, planet carrier132, and ring gear 136 of second planetary gearset 110 all rotatetogether as a single unit. The same effect may be realized by couplingany two of sun gear 130, planet carrier 132, and ring gear 136 together.In one example, sixth selective coupler 172 is fixedly coupled to sungear 130 of second planetary gearset 110 and planet carrier 132 ofsecond planetary gearset 110. In this example, when sixth selectivecoupler 172 is engaged, sun gear 130 of second planetary gearset 110 andplanet carrier 132 of second planetary gearset 110 are locked togetherresulting in all of sun gear 130, planet carrier 132, and ring gear 136of second planetary gearset 110 rotating together as a single unit. Inanother example, sixth selective coupler 172 is fixedly coupled toplanet carrier 132 of second planetary gearset 110 and ring gear 136 ofsecond planetary gearset 110. In this example, when sixth selectivecoupler 172 is engaged, planet carrier 132 of second planetary gearset110 and ring gear 136 of second planetary gearset 110 are lockedtogether resulting in all of sun gear 130, planet carrier 132, and ringgear 136 of second planetary gearset 110 rotating together as a singleunit.

By engaging various combinations of first selective coupler 162, secondselective coupler 164, third selective coupler 166, fourth selectivecoupler 168, fifth selective coupler 170, and sixth selective coupler172, additional components of multi-speed transmission 100 may befixedly coupled together.

In the illustrated embodiment of transmission 100, input member 102 iscoupled to first planetary gearset 108, second planetary gearset 110,third planetary gearset 112, and fourth planetary gearset 114 onlythrough fourth selective coupler 168 and fifth selective coupler 170.Fourth selective coupler 168, when engaged, fixedly couples input member102 to a first group of the plurality of planetary gearsets,illustratively first planetary gearset 108 and second planetary gearset110. Fifth selective coupler 170, when engaged, fixedly couples inputmember 102 to a second group of the plurality of planetary gearsets,illustratively fourth planetary gearset 114. Each of the first group ofthe plurality of planetary gearsets and the second group of theplurality of planetary gearsets may include a single planetary gearsetor a plurality of planetary gearsets. Further, each of first planetarygearset 108, second planetary gearset 110, third planetary gearset 112,and fourth planetary gearset 114 may be included in one or both of thefirst group of the plurality of planetary gearsets and the second groupof the plurality of planetary gearsets.

The plurality of planetary gearsets and the plurality of selectivecouplers of multi-speed transmission 100 may be interconnected invarious arrangements to provide torque from input member 102 to outputmember 104 in at least nine forward gear or speed ratios and one reversegear or speed ratio. Referring to FIG. 2, an exemplary truth table 200is shown that provides the state of each of first selective coupler 162,second selective coupler 164, third selective coupler 166, fourthselective coupler 168, fifth selective coupler 170, and sixth selectivecoupler 172 for ten different forward gear or speed ratios and onereverse gear or speed ratio. Each row corresponds to a giveninterconnection arrangement for transmission 100. The first columnprovides the gear range (reverse and 1^(st)-10^(th) forward gears). Thesecond column provides the gear ratio between the input member 102 andthe output member 104. The third column provides the gear step. The sixrightmost columns illustrate which ones of the selective couplers162-172 are engaged (“1” indicates engaged) and which ones of selectivecouplers 162-172 are disengaged (“(blank)” indicates disengaged). FIG. 2is only one example of any number of truth tables possible for achievingat least nine forward ratios and one reverse ratio.

In the example of FIG. 2, the illustrated reverse ratio (Rev) isachieved by having first selective coupler 162, fourth selective coupler168, and sixth selective coupler 172 in an engaged configuration andsecond selective coupler 164, third selective coupler 166, and fifthselective coupler 170 in a disengaged configuration.

In one embodiment, to place multi-speed transmission 100 in neutral(Neu), all of first selective coupler 162, second selective coupler 164,third selective coupler 166, fourth selective coupler 168, fifthselective coupler 170, and sixth selective coupler 172 are in thedisengaged configuration. One or more of first selective coupler 162,second selective coupler 164, third selective coupler 166, fourthselective coupler 168, fifth selective coupler 170, and sixth selectivecoupler 172 may remain engaged in neutral (Neu) as long as thecombination of first selective coupler 162, second selective coupler164, third selective coupler 166, fourth selective coupler 168, fifthselective coupler 170, and sixth selective coupler 172 does not transmittorque from input member 102 to output member 104.

A first forward ratio (shown as 1st) in truth table 200 of FIG. 2 isachieved by having first selective coupler 162, third selective coupler166, and fourth selective coupler 168 in an engaged configuration andsecond selective coupler 164, fifth selective coupler 170, and sixthselective coupler 172 in a disengaged configuration.

A second or subsequent forward ratio (shown as 2nd) in truth table 200of FIG. 2 is achieved by having first selective coupler 162, thirdselective coupler 166, and fifth selective coupler 170 in an engagedconfiguration and second selective coupler 164, fourth selective coupler168, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the first forward ratio and thesecond forward ratio, fourth selective coupler 168 is placed in thedisengaged configuration and fifth selective coupler 170 is placed inthe engaged configuration.

A third or subsequent forward ratio (shown as 3rd) in truth table 200 ofFIG. 2 is achieved by having third selective coupler 166, fourthselective coupler 168, and fifth selective coupler 170 in an engagedconfiguration and first selective coupler 162, second selective coupler164, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the second forward ratio and thethird forward ratio, first selective coupler 162 is placed in thedisengaged configuration and fourth selective coupler 168 is placed inthe engaged configuration.

A fourth or subsequent forward ratio (shown as 4th) in truth table 200of FIG. 2 is achieved by having second selective coupler 164, thirdselective coupler 166, and fifth selective coupler 170 in an engagedconfiguration and first selective coupler 162, fourth selective coupler168, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the third forward ratio and thefourth forward ratio, fourth selective coupler 168 is placed in thedisengaged configuration and second selective coupler 164 is placed inthe engaged configuration.

A fifth or subsequent forward ratio (shown as 5th) in truth table 200 ofFIG. 2 is achieved by having third selective coupler 166, fifthselective coupler 170, and sixth selective coupler 172 in an engagedconfiguration and first selective coupler 162, second selective coupler164, and fourth selective coupler 168 in a disengaged configuration.Therefore, when transitioning between the fourth forward ratio and thefifth forward ratio, second selective coupler 164 is placed in thedisengaged configuration and sixth selective coupler 172 is placed inthe engaged configuration.

A sixth or subsequent forward ratio (shown as 6th) in truth table 200 ofFIG. 2 is achieved by having second selective coupler 164, fifthselective coupler 170, and sixth selective coupler 172 in an engagedconfiguration and first selective coupler 162, third selective coupler166, and fourth selective coupler 168 in a disengaged configuration.Therefore, when transitioning between the fifth forward ratio and thesixth forward ratio, third selective coupler 166 is placed in thedisengaged configuration and second selective coupler 164 is placed inthe engaged configuration.

A seventh or subsequent forward ratio (shown as 7th) in truth table 200of FIG. 2 is achieved by having fourth selective coupler 168, fifthselective coupler 170, and sixth selective coupler 172 in an engagedconfiguration and first selective coupler 162, second selective coupler164, and third selective coupler 166 in a disengaged configuration.Therefore, when transitioning between the sixth forward ratio and theseventh forward ratio, second selective coupler 164 is placed in thedisengaged configuration and fourth selective coupler 168 is placed inthe engaged configuration.

An eighth or subsequent forward ratio (shown as 8th) in truth table 200of FIG. 2 is achieved by having second selective coupler 164, fourthselective coupler 168, and fifth selective coupler 170 in an engagedconfiguration and first selective coupler 162, third selective coupler166, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the seventh forward ratio and theeighth forward ratio, sixth selective coupler 172 is placed in thedisengaged configuration and second selective coupler 164 is placed inthe engaged configuration.

A ninth or subsequent forward ratio (shown as 9th) in truth table 200 ofFIG. 2 is achieved by having second selective coupler 164, fourthselective coupler 168, and sixth selective coupler 172 in an engagedconfiguration and first selective coupler 162, third selective coupler166, and fifth selective coupler 170 in a disengaged configuration.Therefore, when transitioning between the eighth forward ratio and theninth forward ratio, fifth selective coupler 170 is placed in thedisengaged configuration and sixth selective coupler 172 is placed inthe engaged configuration.

A tenth or subsequent forward ratio (shown as 10th) in truth table 200of FIG. 2 is achieved by having second selective coupler 164, thirdselective coupler 166, and fourth selective coupler 168 in an engagedconfiguration and first selective coupler 162, fifth selective coupler170, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the ninth forward ratio and thetenth forward ratio, sixth selective coupler 172 is placed in thedisengaged configuration and third selective coupler 166 is placed inthe engaged configuration.

The present disclosure contemplates that downshifts follow the reversesequence of the corresponding upshift (as described above). Further,several power-on skip-shifts that are single-transition are possible(e.g. from 1^(st) up to 3^(rd), from 3^(rd) down to 1^(st), from 3^(rd)up to 5^(th), and from 5^(th) down to 3^(rd)).

FIG. 3 is a diagrammatic representation of a multi-speed transmission300. Multi-speed transmission 300 includes an input member 302 and anoutput member 304. Each of input member 302 and output member 304 isrotatable relative to at least one stationary member 306. An exemplaryinput member 302 is an input shaft or other suitable rotatablecomponent. An exemplary output member 304 is an output shaft or othersuitable rotatable component. An exemplary stationary member 306 is ahousing of multi-speed transmission 300. The housing may include severalcomponents coupled together.

Multi-speed transmission 300 includes a plurality of planetary gearsets,illustratively a first planetary gearset 308, a second planetary gearset310, a third planetary gearset 312, and a fourth planetary gearset 314.In one embodiment, additional planetary gearsets may be included.Further, although first planetary gearset 308, second planetary gearset310, third planetary gearset 312, and fourth planetary gearset 314 areillustrated as simple planetary gearsets, it is contemplated thatcompound planetary gearsets may be included in some embodiments.

In one embodiment, multi-speed transmission 300 is arranged asillustrated in FIG. 1, with first planetary gearset 308 positionedbetween a first location or end 316 at which input member 302 entersstationary member 306 and second planetary gearset 310, second planetarygearset 310 is positioned between first planetary gearset 308 and thirdplanetary gearset 312, third planetary gearset 312 is positioned betweensecond planetary gearset 310 and fourth planetary gearset 314, andfourth planetary gearset 314 is positioned between third planetarygearset 312 and a second location or end 318 at which output member 304exits stationary member 306. In alternative embodiments, first planetarygearset 308, second planetary gearset 310, third planetary gearset 312,and fourth planetary gearset 314 are arranged in any order relative tolocation 316 and location 318. In the illustrated embodiment of FIG. 1,each of first planetary gearset 308, second planetary gearset 310, thirdplanetary gearset 312, and fourth planetary gearset 314 are axiallyaligned. In one example, input member 302 and output member 304 are alsoaxially aligned with first planetary gearset 308, second planetarygearset 310, third planetary gearset 312, and fourth planetary gearset314. In alternative embodiments, one or more of input member 302, outputmember 304, first planetary gearset 308, second planetary gearset 310,third planetary gearset 312, and fourth planetary gearset 314 are offsetand not axially aligned with the remainder.

First planetary gearset 308 includes a sun gear 320, a planet carrier322 supporting a plurality of planet gears 324, and a ring gear 326.Second planetary gearset 310 includes a sun gear 330, a planet carrier332 supporting a plurality of planet gears 334, and a ring gear 336.Third planetary gearset 312 includes a sun gear 340, a planet carrier342 supporting a plurality of planet gears 344, and a ring gear 346.Fourth planetary gearset 314 includes a sun gear 350, a planet carrier352 supporting a plurality of planet gears 354, and a ring gear 356.

Multi-speed transmission 300 further includes a plurality of selectivecouplers, illustratively a first selective coupler 362, a secondselective coupler 364, a third selective coupler 366, a fourth selectivecoupler 368, a fifth selective coupler 370, and a sixth selectivecoupler 372. In the illustrated embodiment, first selective coupler 362,second selective coupler 364, and third selective coupler 366 are brakesand fourth selective coupler 368, fifth selective coupler 370, and sixthselective coupler 372 are clutches. The axial locations of the clutchesand brakes relative to the plurality of planetary gearsets may bealtered from the illustrated axial locations.

Multi-speed transmission 300 includes several components that areillustratively shown as being fixedly coupled together. Input member 302is fixedly coupled to fourth selective coupler 368 and fifth selectivecoupler 370. Output member 304 is fixedly coupled to planet carrier 352of fourth planetary gearset 314 and ring gear 346 of third planetarygearset 312. Ring gear 356 of fourth planetary gearset 314, planetcarrier 342 of third planetary gearset 312, first selective coupler 362,and sixth selective coupler 372 are fixedly coupled together. Ring gear336 of second planetary gearset 310 and sun gear 340 of third planetarygearset 312 are fixedly coupled together. Sun gear 330 of secondplanetary gearset 310, ring gear 326 of first planetary gearset 308,sixth selective coupler 372, and fourth selective coupler 368 arefixedly coupled together. Planet carrier 322 of first planetary gearset308, planet carrier 332 of second planetary gearset 310, and secondselective coupler 364 are fixedly coupled together. Sun gear 350 offourth planetary gearset 314 is fixedly coupled to fifth selectivecoupler 370. Sun gear 320 of first planetary gearset 308 is fixedlycoupled to third selective coupler 366.

Multi-speed transmission 300 may be described as having eightinterconnectors. Input member 302 is a first interconnector that bothprovides input torque to multi-speed transmission 300 and fixedlycouples fourth selective coupler 368 to fifth selective coupler 370.Output member 304 is a second interconnector that both provides outputtorque from multi-speed transmission 300 and fixedly couples planetcarrier 352 of fourth planetary gearset 314 to ring gear 346 of thirdplanetary gearset 312. A third interconnector 380 fixedly couples ringgear 356 of fourth planetary gearset 314, planet carrier 342 of thirdplanetary gearset 312, sixth selective coupler 372, and first selectivecoupler 362 together. A fourth interconnector 382 fixedly couples ringgear 336 of second planetary gearset 310 to sun gear 340 of thirdplanetary gearset 312. A fifth interconnector 384 fixedly couples ringgear 326 of first planetary gearset 308, sun gear 330 of secondplanetary gearset 310, fourth selective coupler 368, and sixth selectivecoupler 372 together. A sixth interconnector 386 fixedly couples planetcarrier 322 of first planetary gearset 308, planet carrier 332 of secondplanetary gearset 310, and second selective coupler 364 together. Aseventh interconnector 388 fixedly couples sun gear 350 of fourthplanetary gearset 314 to fifth selective coupler 370. An eighthinterconnector 390 fixedly couples sun gear 320 of first planetarygearset 308 to third selective coupler 366.

Multi-speed transmission 300 further includes several components thatare illustratively shown as being selectively coupled together throughselective couplers. First selective coupler 362, when engaged, fixedlycouples ring gear 356 of fourth planetary gearset 314 and planet carrier342 of third planetary gearset 312 to stationary member 306. When firstselective coupler 362 is disengaged, ring gear 356 of fourth planetarygearset 314 and planet carrier 342 of third planetary gearset 312 mayrotate relative to stationary member 306.

Second selective coupler 364, when engaged, fixedly couples planetcarrier 322 of first planetary gearset 308 and planet carrier 332 ofsecond planetary gearset 310 to stationary member 306. When secondselective coupler 364 is disengaged, planet carrier 322 of firstplanetary gearset 308 and planet carrier 332 of second planetary gearset310 may rotate relative to stationary member 306.

Third selective coupler 366, when engaged, fixedly couples sun gear 320of first planetary gearset 308 to stationary member 306. When thirdselective coupler 366 is disengaged, sun gear 320 of first planetarygearset 308 may rotate relative to stationary member 306.

Fourth selective coupler 368, when engaged, fixedly couples input member302 to ring gear 326 of first planetary gearset 308 and sun gear 330 ofsecond planetary gearset 310. When fourth selective coupler 368 isdisengaged, ring gear 326 of first planetary gearset 308 and sun gear330 of second planetary gearset 310 may rotate relative to input member302.

Fifth selective coupler 370, when engaged, fixedly couples input member302 to sun gear 350 of fourth planetary gearset 314. When fifthselective coupler 370 is disengaged, sun gear 350 of fourth planetarygearset 314 may rotate relative to input member 102.

Sixth selective coupler 372, when engaged, fixedly couples ring gear 326of first planetary gearset 308 and sun gear 330 of second planetarygearset 310 to planet carrier 342 of third planetary gearset 312 andring gear 356 of fourth planetary gearset 314. When sixth selectivecoupler 372 is disengaged, ring gear 326 of first planetary gearset 308and sun gear 330 of second planetary gearset 310 may rotate relative toplanet carrier 342 of third planetary gearset 312 and ring gear 356 offourth planetary gearset 314.

By engaging various combinations of first selective coupler 362, secondselective coupler 364, third selective coupler 366, fourth selectivecoupler 368, fifth selective coupler 370, and sixth selective coupler372, additional components of multi-speed transmission 300 may befixedly coupled together.

In the illustrated embodiment of transmission 300, input member 302 iscoupled to first planetary gearset 308, second planetary gearset 310,third planetary gearset 312, and fourth planetary gearset 314 onlythrough fourth selective coupler 368 and fifth selective coupler 370.Fourth selective coupler 368, when engaged, fixedly couples input member302 to a first group of the plurality of planetary gearsets,illustratively first planetary gearset 308 and second planetary gearset310. Fifth selective coupler 170, when engaged, fixedly couples inputmember 302 to a second group of the plurality of planetary gearsets,illustratively fourth planetary gearset 314. Each of the first group ofthe plurality of planetary gearsets and the second group of theplurality of planetary gearsets may include a single planetary gearsetor a plurality of planetary gearsets. Further, each of first planetarygearset 308, second planetary gearset 310, third planetary gearset 312,and fourth planetary gearset 314 may be included in one or both of thefirst group of the plurality of planetary gearsets and the second groupof the plurality of planetary gearsets.

The plurality of planetary gearsets and the plurality of selectivecouplers of multi-speed transmission 300 may be interconnected invarious arrangements to provide torque from input member 302 to outputmember 304 in at least nine forward gear or speed ratios and one reversegear or speed ratio. Referring to FIG. 4, an exemplary truth table 400is shown that provides the state of each of first selective coupler 362,second selective coupler 364, third selective coupler 366, fourthselective coupler 368, fifth selective coupler 370, and sixth selectivecoupler 372 for ten different forward gear or speed ratios and onereverse gear or speed ratio. Each row corresponds to a giveninterconnection arrangement for transmission 300. The first columnprovides the gear range (reverse and 1^(st)-10^(th) forward gears). Thesecond column provides the gear ratio between the input member 302 andthe output member 304. The third column provides the gear step. The sixrightmost columns illustrate which ones of the selective couplers362-372 are engaged (“1” indicates engaged) and which ones of selectivecouplers 362-372 are disengaged (“(blank)” indicates disengaged). FIG. 4is only one example of any number of truth tables possible for achievingat least nine forward ratios and one reverse ratio.

In the example of FIG. 4, the illustrated reverse ratio (Rev) isachieved by having first selective coupler 362, third selective coupler366, and fourth selective coupler 368 in an engaged configuration andsecond selective coupler 364, fifth selective coupler 370, and sixthselective coupler 372 in a disengaged configuration.

In one embodiment, to place multi-speed transmission 300 in neutral(Neu), all of first selective coupler 362, second selective coupler 364,third selective coupler 366, fourth selective coupler 368, fifthselective coupler 370, and sixth selective coupler 372 are in thedisengaged configuration. One or more of first selective coupler 362,second selective coupler 364, third selective coupler 366, fourthselective coupler 368, fifth selective coupler 370, and sixth selectivecoupler 372 may remain engaged in neutral (Neu) as long as thecombination of first selective coupler 362, second selective coupler364, third selective coupler 366, fourth selective coupler 368, fifthselective coupler 370, and sixth selective coupler 372 does not transmittorque from input member 302 to output member 304.

A first forward ratio (shown as 1st) in truth table 400 of FIG. 4 isachieved by having first selective coupler 362, second selective coupler364, and fourth selective coupler 368 in an engaged configuration andthird selective coupler 366, fifth selective coupler 370, and sixthselective coupler 372 in a disengaged configuration.

A second or subsequent forward ratio (shown as 2nd) in truth table 400of FIG. 4 is achieved by having first selective coupler 362, fourthselective coupler 368, and fifth selective coupler 370 in an engagedconfiguration and second selective coupler 364, third selective coupler366, and sixth selective coupler 372 in a disengaged configuration.Therefore, when transitioning between the first forward ratio and thesecond forward ratio, second selective coupler 364 is placed in thedisengaged configuration and fifth selective coupler 370 is placed inthe engaged configuration.

A third or subsequent forward ratio (shown as 3rd) in truth table 400 ofFIG. 4 is achieved by having second selective coupler 364, fourthselective coupler 368, and fifth selective coupler 370 in an engagedconfiguration and first selective coupler 362, third selective coupler366, and sixth selective coupler 372 in a disengaged configuration.Therefore, when transitioning between the second forward ratio and thethird forward ratio, first selective coupler 362 is placed in thedisengaged configuration and second selective coupler 364 is placed inthe engaged configuration.

A fourth or subsequent forward ratio (shown as 4th) in truth table 400of FIG. 4 is achieved by having second selective coupler 364, fifthselective coupler 370, and sixth selective coupler 372 in an engagedconfiguration and first selective coupler 362, third selective coupler366, and fourth selective coupler 368 in a disengaged configuration.Therefore, when transitioning between the third forward ratio and thefourth forward ratio, fourth selective coupler 368 is placed in thedisengaged configuration and sixth selective coupler 372 is placed inthe engaged configuration.

A fifth or subsequent forward ratio (shown as 5th) in truth table 400 ofFIG. 4 is achieved by having second selective coupler 364, thirdselective coupler 366, and fifth selective coupler 370 in an engagedconfiguration and first selective coupler 362, fourth selective coupler368, and sixth selective coupler 372 in a disengaged configuration.Therefore, when transitioning between the fourth forward ratio and thefifth forward ratio, sixth selective coupler 372 is placed in thedisengaged configuration and third selective coupler 366 is placed inthe engaged configuration.

A sixth or subsequent forward ratio (shown as 6th) in truth table 400 ofFIG. 4 is achieved by having third selective coupler 366, fifthselective coupler 370, and sixth selective coupler 372 in an engagedconfiguration and first selective coupler 362, second selective coupler364, and fourth selective coupler 368 in a disengaged configuration.Therefore, when transitioning between the fifth forward ratio and thesixth forward ratio, second selective coupler 364 is placed in thedisengaged configuration and sixth selective coupler 372 is placed inthe engaged configuration.

A seventh or subsequent forward ratio (shown as 7th) in truth table 400of FIG. 4 is achieved by having third selective coupler 366, fourthselective coupler 368, fifth selective coupler 370 in an engagedconfiguration and first selective coupler 362, second selective coupler364, and sixth selective coupler 372 in a disengaged configuration.Therefore, when transitioning between the sixth forward ratio and theseventh forward ratio, sixth selective coupler 372 is placed in thedisengaged configuration and fourth selective coupler 368 is placed inthe engaged configuration.

An eighth or subsequent forward ratio (shown as 8th) in truth table 400of FIG. 4 is achieved by having fourth selective coupler 368, fifthselective coupler 370, and sixth selective coupler 372 in an engagedconfiguration and first selective coupler 362, second selective coupler364, and third selective coupler 366 in a disengaged configuration.Therefore, when transitioning between the seventh forward ratio and theeighth forward ratio, third selective coupler 366 is placed in thedisengaged configuration and sixth selective coupler 372 is placed inthe engaged configuration.

A ninth or subsequent forward ratio (shown as 9th) in truth table 400 ofFIG. 4 is achieved by having third selective coupler 366, fourthselective coupler 368, and sixth selective coupler 372 in an engagedconfiguration and first selective coupler 362, second selective coupler364, and fifth selective coupler 370 in a disengaged configuration.Therefore, when transitioning between the eighth forward ratio and theninth forward ratio, fifth selective coupler 370 is placed in thedisengaged configuration and third selective coupler 366 is placed inthe engaged configuration.

A tenth or subsequent forward ratio (shown as 10th) in truth table 400of FIG. 4 is achieved by having second selective coupler 364, fourthselective coupler 368, and sixth selective coupler 372 in an engagedconfiguration and first selective coupler 362, third selective coupler366, and fifth selective coupler 370 in a disengaged configuration.Therefore, when transitioning between the ninth forward ratio and thetenth forward ratio, third selective coupler 366 is placed in thedisengaged configuration and second selective coupler 364 is placed inthe engaged configuration.

The present disclosure contemplates that downshifts follow the reversesequence of the corresponding upshift (as described above). Further,several power-on skip-shifts that are single-transition are possible(e.g. from 1^(st) up to 3^(rd), from 3^(rd) down to 1^(st), from 3^(rd)up to 5^(th), and from 5^(th) down to 3^(rd)).

In the illustrated embodiments, various combinations of three of theavailable selective couplers are engaged for each of the illustratedforward speed ratios and reverse speed ratios. Additional forward speedratios and reverse speed ratios are possible based on other combinationsof engaged selective couplers. Although in the illustrated embodiments,each forward speed ratio and reverse speed ratio has three of theavailable selective couplers engaged, it is contemplated that less thanthree and more than three selective couplers may be engaged at the sametime.

While this invention has been described as having exemplary designs, thepresent invention can be further modified within the spirit and scope ofthis disclosure. This application is therefore intended to cover anyvariations, uses, or adaptations of the invention using its generalprinciples. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains and which fallwithin the limits of the appended claims.

What is claimed is:
 1. A transmission comprising: at least onestationary member; an input member rotatable relative to the at leastone stationary member; a plurality of planetary gearsets operativelycoupled to the input member, each of the plurality of planetary gearsetsincluding a first gearset component, a second gearset component, and athird gearset component, the plurality of planetary gearsets including afirst planetary gearset, a second planetary gearset, a third planetarygearset, and a fourth planetary gearset; an output member operativelycoupled to the input member through the plurality of planetary gearsetsand rotatable relative to the at least one stationary member, the outputmember is fixedly coupled to the second gearset component of the fourthplanetary gearset and the third gearset component of the third planetarygearset; a first interconnector which fixedly couples the third gearsetcomponent of the fourth planetary gearset to the second gearsetcomponent of the third planetary gearset; a second interconnector whichfixedly couples the first gearset component of the third planetarygearset to the third gearset component of the second planetary gearset;a third interconnector which fixedly couples the third gearset componentof the first planetary gearset to the first gearset component of thesecond planetary gearset; a fourth interconnector which fixedly couplesthe second gearset component of the first planetary gearset to thesecond gearset component of the second planetary gearset; and aplurality of selective couplers, wherein the plurality of selectivecouplers includes: a first selective coupler which, when engaged,fixedly couples the third gearset component of the fourth planetarygearset and the second gearset component of the third planetary gearsetto the at least one stationary member; a second selective coupler which,when engaged, fixedly couples the second gearset component of the firstplanetary gearset and the second gearset component of the secondplanetary gearset to the at least one stationary member; a thirdselective coupler which, when engaged, fixedly couples the first gearsetcomponent of the first planetary gearset to the at least one stationarymember; a fourth selective coupler which, when engaged, fixedly couplesthe input member to the third gearset component of the first planetarygearset and to the first gearset component of the second planetarygearset; a fifth selective coupler which, when engaged, fixedly couplesthe input member to the first gearset component of the fourth planetarygearset; and a sixth selective coupler which, when engaged, fixedlycouples the third gearset component of the first planetary gearset andthe first gearset component of the second planetary gearset to thesecond gearset component of the third planetary gearset and the thirdgearset component of the fourth planetary gearset.
 2. The transmissionof claim 1, wherein each of the first planetary gearset, the secondplanetary gearset, the third planetary gearset, and the fourth planetarygearset is a simple planetary gearset.
 3. The transmission of claim 2,wherein the first gearset component of the first planetary gearset is afirst sun gear, the first gearset component of the second planetarygearset is a second sun gear, the first gearset component of the thirdplanetary gearset is a third sun gear, the first gearset component ofthe fourth planetary gearset is a fourth sun gear, the second gearsetcomponent of the first planetary gearset is a first planet carrier, thesecond gearset component of the second planetary gearset is a secondplanet carrier, the second gearset component of the third planetarygearset is a third planet carrier, the second gearset component of thefourth planetary gearset is a fourth planet carrier, the third gearsetcomponent of the first planetary gearset is a first ring gear, the thirdgearset component of the second planetary gearset is a second ring gear,the third gearset component of the third planetary gearset is a thirdring gear, and the third gearset component of the fourth planetarygearset is a fourth ring gear.
 4. The transmission of claim 1, whereinthe at least one stationary member includes a housing, the housinghaving a first end and a second end, wherein the input member isaccessible proximate the first end of the housing; the output member isaccessible proximate the second end of the housing; the first planetarygearset is positioned between the first end of the housing and thesecond planetary gearset; the second planetary gearset is positionedbetween the first planetary gearset and the third planetary gearset; thethird planetary gearset is positioned between the second planetarygearset and the fourth planetary gearset; and the fourth planetarygearset is positioned between the third planetary gearset and the secondend of the housing.
 5. A transmission comprising: at least onestationary member; an input member; a plurality of planetary gearsetsoperatively coupled to the input member, each planetary gearset of theplurality of planetary gearsets including a sun gear, a plurality ofplanet gears operatively coupled to the sun gear, a planet carrieroperatively coupled to the plurality of planet gears, and a ring gearoperatively coupled to the plurality of planet gears, the plurality ofplanetary gearsets including a first planetary gearset, a secondplanetary gearset, a third planetary gearset, and a fourth planetarygearset; a plurality of selective couplers operatively coupled to theplurality of planetary gearsets, each of the plurality of selectivecouplers having an engaged configuration and a disengaged configuration,the plurality of selective couplers including a first number of clutchesand a second number of brakes, the first number being equal to thesecond number; and an output member operatively coupled to the inputmember through the plurality of planetary gearsets, the output memberbeing fixedly coupled to the ring gear of the third planetary gearsetand the planet carrier of the fourth planetary gearset, wherein theinput member is operatively coupled to the plurality of planetarygearsets only through a subset of the first number of clutches, thefirst number of clutches including a first clutch, a second clutch, anda third clutch, the subset including the first clutch and the secondclutch, wherein the first clutch, when engaged, fixedly couples theinput member to a first group of the plurality of planetary gearsets,wherein the first clutch, when engaged, fixedly couples the input memberto the ring gear of the first planetary gearset and the sun gear of thesecond planetary gearset, and the second clutch, when engaged, fixedlycouples the input member to a second group of the plurality of planetarygearsets, wherein the first group includes the first planetary gearsetand the second planetary gearset, the first group and the second groupeach including an equal number of the plurality of planetary gearsets.6. The transmission of claim 5, wherein the second group includes thefourth planetary gearset.
 7. The transmission of claim 5, wherein eachof the first planetary gearset, the second planetary gearset, the thirdplanetary gearset, and the fourth planetary gearset is a simpleplanetary gearset.
 8. The transmission of claim 7, wherein the at leastone stationary member includes a housing, the housing having a first endand a second end, wherein the input member is accessible proximate thefirst end of the housing; the output member is accessible proximate thesecond end of the housing; the first planetary gearset is positionedbetween the first end of the housing and the second planetary gearset;the second planetary gearset is positioned between the first planetarygearset and the third planetary gearset; the third planetary gearset ispositioned between the second planetary gearset and the fourth planetarygearset; and the fourth planetary gearset is positioned between thethird planetary gearset and the second end of the housing.
 9. Thetransmission of claim 8, wherein the plurality of selective couplers areselectively engaged in a plurality of combinations to establish at leastnine forward speed ratios and at least one reverse speed ratio betweenthe input member and the output member, each of the plurality ofcombinations having at least three of the plurality of selectivecouplers engaged.